Method of making laminations



Nov. 23, 1948. E. A. MILLER 2,454,609

IETHOD 0F KING WINATIONS Filed Feb. 21, 1945 o v I INVENTOR. 3 M mauw. Elsi- BY Patented Nov. 23, 1948 Edward A. Miller, Cuba, N. Y.,

lgnments, to Acme Electric Corporation, a

aaaignor, by mesne corporation of New York Application February 21, 1945, Serial No. 578,127

My invention relates in general to laminations for laminated cores having rounded corners and the method otconstructing these laminations.

It is an object of my invention to construct, from a strip of sheet metal and with a minimum of waste, U-shaped laminations having the outer corners rounded.

Another object of my invention relates to the use of rounded corners on laminations to conserve space and provide wiring room in the casing which encloses the laminated core.

A further object of myinven'tion relates to the process of constructing from a strip of sheet metal two interlocking U-shaped laminations by punching fastening holes and notches for rounded comers in the sides of the strip and finally cutting along substantially an S-shaped cutting line, the line being so proportioned that each of the U-shaped pieces has a base and two arms of unequal length.

Other objects and a fuler understanding of ,my invention may be had by referring to the following description and claim, taken in conjunction with the accompanying drawing, in which:

Figure 1 is a plan view illustrating the method of forming the U-shaped laminations from a strip of sheet metal;

Figure 2 is a view of the U-shaped lamination;

Figure 3 is a view of the end piece;

Figure 4 is a perspective showing the manner in which laminations are-assembled into a core; and

Figure 5 is a view of an assembled core.

With reference to the drawing, the reference character In illustrates a strip of sheet metal from which the U-shaped laminations ll may be formed by a suitable machine having a progressive die to make the first two laminations which are shown in the left end of the strip in in Figure 1. The width of the strip of sheet metal is equal to the length of the U-shaped lamination. As the strip of sheet metal progresses through the die the holes l2 are punched in the metal, and the V-shaped notches i3 and i4 and the rectangularly shaped notches i5 and it are punched from the side edges. One side edge of the rectangularly shaped notches i5 and i 6 is straight and the other side edge i9 is rounded, that is, it tangently approaches the side of the sheet of metal. The side edge I! cuts the base I! of the rectangular notch at point 24. In another operation, the U-shaped laminations i i are blanked from the strip. These laminations Ii, are formed by cutting between the bases of the V-shaped notches along a line 28 and also along an 8-shaped line 28 between the 1 Claim. (01. 184-18) rectangular notches.

edge 2| and the side edge 22 -2 The 25 extends from a point Ill, tance i'rom point 24 on base ing, on the base It of notch l8 along a line perpendicular to the'edge of the strip to point 3|. From point ii, the cutting line extends parallel to the edge of the strip ill a distance equal to the width of the arm of the U-shaped lamination to point 32. From point 32 the cutting line extends perpendicular to the cutting edge to a point 33, thence parallel to the edge to point 34, points 83 and 34 being separated by a distance equal to the width of the arm. From point 34, the cutting line extends ina perpendicular direction to theedge of the strip to a point 35 which is located on the base of the notch IS. The forming of the rectangular notches allows the use of a larger punch for preventing breakage of tools and for rounding the'corners, thus eliminating another punching operation. The V-shaped notches have a short base". The cutting l ne 22 cuts the base ll providing a small step 20 between the rounded and eliminating formation of slivers on the edges. The other rounded edges approach tangently the side edge of the strip of sheet metal ill. The completed lamination is as shown in Figure 2.

The end pieces, having reference character 23 and illustrated in Figure 3, may be punched several at a time from separate sheets of material by using a suitable punch and die.

The laminations are stacked as shown in F gure 4, having the end pieces 23 alternately inserted between the arms, of the U-shaped laminations H and having a short arm between two long arms. The stacks may be held together to form a core by rivets or other suitable fastening means extending through the holes i2. In this manner a strong magnetic core having rounded edges may be formed with a minimum waste of materia Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted s-shaped cutting line located a short dislil to prevent silverto without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim as my invention:

The method of constructing U-shaped laminations from a strip of material, said laminations having a base with rounded outer corners and having side arms of unequal length with the longer of said arms having a step on the inside corner and a rounded outer corner, said method comprising the successive steps of, punching a somewhat V-shaped notch in each side edge of the strip with each notch defining a first edge parallel to the side edge of the strip and also defining first corner edge portions meeting the ends of the first edge and curving into the side edge of the strip, punching somewhat rectangular shaped notches in each side edge of the strip with each somewhat rectangular shaped notch defining a first step edge parallel to the side edge of the strip, a second step edge extending between one end of the first step edge and the side edge, and a second corner edge portion extending from the other end of said first step edge and curving into the side edge of the-strip,' and blanking the U-shaped lamination from the strip with a part of the first edge, and the respective first corner edge portion of the V-shaped notch on.

one side of the strip forming a rounded corner on the base of the lamination, with a part of the first edge and the respective first corner edge portion of the V-shaped notch in the opposite side edge of the strip forming a rounded outside corner on the longer arm, with a part of the first step edge and the second corner edge portion of the somewhat rectangu ar shaped notch in one side edge of the strip forming the other rounded corner on the base of the lamination, and with a part of the first step edge and the second step edge of the somewhat rectangular shaped notch in the other side edge of the strip forming the step on the inside corner of the longer of said arms.

EDWARD A. MILLER. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTs 

